Dihadron angular correlations in d + Au collisions at √s NN = 200 GeVare reported as a function of the measured zero-degree calorimeter neutral energy and the forward charged hadron multiplicity in the Au-beam direction. A finite correlated yield is observed at large relative pseudorapidity (Δ η) on the near side (i.e. relative azimuth Δ Φ ~ 0). This correlated yield as a function of Δη appears to scale with the dominant, primarily jet-related, away-side (Δ Φ ~ π) yield. The Fourier coefficients of the ΔΦ correlation, V n = cosn ΔΦ , have a strong Δη dependence. In addition, it is found that V 1 is approximately inversely proportional to the mid-rapidity event multiplicity, while V 2 is independent of it with similar magnitude in the forward (d-going) and backward (Au-going) directions.

Dihadron angular correlations in d + Au collisions at √s NN = 200 GeVare reported as a function of the measured zero-degree calorimeter neutral energy and the forward charged hadron multiplicity in the Au-beam direction. A finite correlated yield is observed at large relative pseudorapidity (Δ η) on the near side (i.e. relative azimuth Δ Φ ~ 0). This correlated yield as a function of Δη appears to scale with the dominant, primarily jet-related, away-side (Δ Φ ~ π) yield. The Fourier coefficients of the ΔΦ correlation, V n = cosn ΔΦ , have a strong Δη dependence. In addition,more » it is found that V 1 is approximately inversely proportional to the mid-rapidity event multiplicity, while V 2 is independent of it with similar magnitude in the forward (d-going) and backward (Au-going) directions.« less

In this study, dihadron angular correlations in d+Au collisions at √s NN=200 GeV are reported as a function of the measured zero-degree calorimeter neutral energy and the forward charged hadron multiplicity in the Au-beam direction. A finite correlated yield is observed at large relative pseudorapidity (Δη) on the near side (i.e. relative azimuth ΔΦ~0). This correlated yield as a function of Δη appears to scale with the dominant, primarily jet-related, away-side (ΔΦ~π) yield. The Fourier coefficients of the ΔΦ correlation, V n={cosnΔΦ}, have a strong Δη dependence. In addition, it is found that V 1 is approximately inversely proportional tomore » the mid-rapidity event multiplicity, while V 2 is independent of it with similar magnitude in the forward (d-going) and backward (Au-going) directions.« less

We present measurements of two-particle angular correlations between high-transverse-momentum (2 < p T < 11 GeV/c)π 0 observed at midrapidity (|η| < 0.35) and particles produced either at forward (3.1 < η < 3.9) or backward (- 3.7 < η < -3.1) rapidity in d + Au and p + p collisions atmore » $$\sqrt{s}$$$_ {NN}$$ = 200 GeV. The azimuthal angle correlations for particle pairs with this large rapidity gap in the Au-going direction exhibit a characteristic structure that persists up to p T ≈ 6 GeV/c and which strongly depends on collision centrality, which is a similar characteristic to the hydrodynamical particle flow in A + A collisions. The structure is absent in the d-going direction as well as in p + p collisions, in the transverse-momentum range studied. The results indicate that the structure is shifted in the Au-going direction toward more central collisions, similar to the charged-particle pseudorapidity distributions.« less

Dihadron correlations at high transverse momentum p{sub T} in d+Au collisions at {radical}(s{sub NN})=200 GeV at midrapidity are measured by the PHENIX experiment at the Relativistic Heavy Ion Collider. From these correlations, we extract several structural characteristics of jets: the root-mean-squared transverse momentum of fragmenting hadrons with respect to the jet {radical}(<j{sub T}{sup 2}>), the mean sine-squared of the azimuthal angle between the jet axes <sin{sup 2}{phi}{sub jj}>, and the number of particles produced within the dijet that are associated with a high-p{sub T} particle (dN/dx{sub E} distributions). We observe that the fragmentation characteristics of jets in d+Au collisions aremore » very similar to those in p+p collisions and that there is little dependence on the centrality of the d+Au collision. This is consistent with the nuclear medium having little influence on the fragmentation process. Furthermore, there is no statistically significant increase in the value of <sin{sup 2}{phi}{sub jj}> from p+p to d+Au collisions. This constrains the effect of multiple scattering that partons undergo in the cold nuclear medium before and after a hard collision.« less